Magnetic one-component toner and magnetic one-component development method

Abstract

The magnetic one-component toner of the present invention is used for a developing device having a stainless-steel development sleeve and satisfies the following formulas (i), (ii), (iii) and (iv). The magnetic one-component development is to develop by using the magnetic one-component toner and rotating a stainless-steel development sleeve at a circumferential velocity of not less than 360 mm/second. Thereby, it is possible to inhibit the occurrence of layer irregularity. A ≦ 11 ( i ) 4 ≦ B ( ii ) 0.4 ≦ B A ≦ 0.8 ( iii ) A × C ≦ 800 ( iv ) wherein A represents a frictional charge amount (μC/g) after agitating 5 parts by weight of magnetic one-component toner and 95 parts by weight of non-coated ferrite carrier for one minute, B represents a frictional charge amount (μC/g) after agitating 5 parts by weight of magnetic one-component toner and 95 parts by weight of non-coated ferrite carrier for 30 minutes, and C represents a passage rate of toner (%).

1 . A magnetic one-component toner, which is used for a developing device having a stainless-steel development sleeve and satisfies the following formulas (i), (ii), (iii) and (iv),  
     
       
         
           
             
               
                 
                   A 
                   ≦ 
                   11 
                 
               
               
                 
                   ( 
                   i 
                   ) 
                 
               
             
             
               
                 
                   4 
                   ≦ 
                   B 
                 
               
               
                 
                   ( 
                   ii 
                   ) 
                 
               
             
             
               
                 
                   0.4 
                   ≦ 
                   
                     B 
                     A 
                   
                   ≦ 
                   0.8 
                 
               
               
                 
                   ( 
                   iii 
                   ) 
                 
               
             
             
               
                 
                   
                     A 
                     × 
                     C 
                   
                   ≦ 
                   800 
                 
               
               
                 
                   ( 
                   iv 
                   ) 
                 
               
             
           
         
       
     
     wherein A represents a frictional charge amount (μC/g) after agitating 5 parts by weight of magnetic one-component toner and 95 parts by weight of non-coated ferrite carrier for one minute, B represents a frictional charge amount (μC/g) after agitating 5 parts by weight of magnetic one-component toner and 95 parts by weight of non-coated ferrite carrier for 30 minutes, and C represents a passage rate of toner (%) calculated by the following formula (v),  
     
       
         
           
             
               
                 
                   
                     Passage 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     rate 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     of 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     toner 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     
                       ( 
                       % 
                       ) 
                     
                   
                   = 
                   
                     
                       
                         Toner 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         amount 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         passed 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         through 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         a 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         sieve 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           ( 
                           g 
                           ) 
                         
                       
                       
                         5 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           ( 
                           g 
                           ) 
                         
                       
                     
                     × 
                     100 
                   
                 
               
               
                 
                   ( 
                   v 
                   ) 
                 
               
             
           
         
       
     
     wherein Toner amount passed through a sieve (g) is measured by using a powder tester (rheostat scale: 2) and passing 5 g of magnetic one-component toner through a 140-mesh vibrating sieve for 30 seconds.  
   
   
       2 . The magnetic one-component toner according to  claim 1 , which is obtained through pulverization classification method.  
   
   
       3 . The magnetic one-component toner according to  claim 1 , containing magnetite having a shape of octahedron and a mean particle size of 0.05 to 1.0 μm as magnetic powder.  
   
   
       4 . A magnetic one-component development method, 
 wherein development is carried out by using a magnetic one-component toner and rotating a stainless-steel development sleeve at a circumferential velocity of not less than 360 mm/second; and    the magnetic one-component toner according to  claim 1  is used as the said magnetic one-component toner.    
   
   
       5 . The magnetic one-component development method according to  claim 4 , wherein the said stainless-steel development sleeve rotates at a circumferential velocity of 360 to 800 mm/second.